The present invention relates to network termination modules that are utilized in telephone network interface apparatus to isolate the telephone company ("telco" herein) portion of the system from that serving the respective subscribers. Such isolation is desirable in order to segregate the responsibility for faults or malfunctions that may occur in the respective parts of the system.
The aforementioned patent applications (the contents of which patent applications are incorporated herein by reference), of which this application is a continuation-in-part, describe a telephone network interface apparatus arrangement utilizing a device, referred to herein as a "network termination module," in which the demarcation between the telco and subscriber portions of the system is established. Such network termination modules are advantageously organized to house within a single base structure those elements, such as a jack, a protector assembly and other apparatus required to interface the wiring for the subscriber telephone service with the incoming telephone wiring. While such devices can be used as single, stand-alone units, they are particularly useful for applications, such as office buildings, apartments, or the like, in which the incoming telephone wiring is intended for use by a multitude of subscribers. The described modules are particularly suited to be stacked in close, side-by-side relation in box-like enclosures, termed the "network interface apparatus", that, depending upon their size, are capable of accommodating any number of modules. Consequently, there results from such devices the ability, not only to segregate that portion of the system which is the responsibility of the subscriber from that for which the telephone company is responsible, but also to permit the centralization of a large number of the devices for ready access, whether by the subscriber or by a telco installer.
It is known to provide security for equipment of the described type by incorporating an enclosure that possesses two covers, one of which can be opened by both telco installers and by subscribers and the other which can be opened solely by the former. In this way, subscriber wiring is accessible by both the subscriber and a telco installer but telco wiring and that portion of the system which is appurtenant thereto can be accessed only by the telco installer.
With the housing within a common enclosure of equipment that provides telephone service to a large number of diverse subscribers, the need for security extends, not only to the interior of the housing, but even to the interior of each module. Thus, it is known to provide individual module with individual security covers and to provide means for locking such covers in place, typically by a padlock that can be opened only by the concerned subscriber. Early efforts in the design of this equipment utilized telco covers which, when opened, permitted removal of the padlock securing the module cover whereupon a telco installer could have access to the module interior. Such efforts are described in U.S. Pat. No. 4,979,209 granted Dec. 18, 1990 to T. J. Collins et al. and assigned to Keptel, Inc.
Through use it has been discovered that apparatus requiting removal of the padlock before access to subscriber wiring in subscriber line or network termination modules of the described type can be obtained by a telephone installer suffers several disadvantages. For example, when a padlock must be removed from the module of a subscriber to permit access to the interior thereof, there is the problem that the lock can be misplaced or lost, thereby denying the subscriber the requisite security until the lock is replaced. Even more troublesome, however, is the fact that, when access is required to such modules, it is readily conceivable that the locks for a pair or more of the modules can be switched or mixed. This, of course, creates the disadvantage that, not only must the lock of the concerned subscriber be replaced, but the lock erroneously put in place must be removed, either by breaking it or by the engagement of a locksmith.
In this regard, there is disclosed in U.S. Pat. No. 4,825,466, granted Apr. 25, 1989, to Dowler et al. and assigned to the assignee herein, an arrangement for enabling authorized access to a telephone interface security device without need to remove the lock. Such arrangement presents a complex organization of parts occupying considerable space thereby making it inappropriate for use with network termination modules of the type described herein.
It is to the amelioration of these and other problems associated with the use of the concerned equipment that the present invention is directed.